Blastocysts are 5 or 6 day old embryos and are at the last free-living stage that can be
studied in the laboratory prior to transfer into the uterus. They contain between 50 and
300 cells that surround a fluid-filled cavity called the blastocoels. The researchers
carefully removed fluid from the blastocoel, leaving the cells intact.
5 day embryo's DNA sampled without biopsy
New research shows that the fluid-filled cavity in 5-day old human blastocysts may contain DNA from the embryo, allowing diagnosis of genetic disease without a biopsy.
Preimplantation genetic diagnosis (PGD) technologies allow identification of genetic disorders in human preimplantation embryos after in vitro fertilization (IVF) and before the embryo is transferred back to the patient. This technique allows couples with a high-risk of passing on inherited diseases, to increase their chances of having a healthy baby. Despite the theoretical benefits of PGD, clinical outcomes using these technologies vary, possibly because of the need to remove one or more cells from the embryo using biopsy.
In a recent study published in Reproductive Biomedicine Online, a group of researchers from Italy and the United Kingdom sought to achieve diagnose of genetic disease in embryonic DNA without the use of a biopsy.
By extracting fluid from human embryos at the blastocyst stage they found that it contains DNA from the embryo. Blastocysts are 5 or 6 day old embryos and are at the last free-living stage that can be studied in the laboratory prior to transfer into the uterus. They contain between 50 and 300 cells that surround a fluid-filled cavity called the blastocoels. The researchers carefully removed fluid from the blastocoel, leaving the cells intact. The sampled blastocysts were subsequently cryopreserved.
Analysis of this fluid showed that it contained cell-free DNA
in a state good enough to determine several known genes
of the sex chromosomes by polymerase chain reaction (PCR);
whole genome amplification and followed by analysis using
a specialized tool for genetic testing called a DNA microarray.
The tests revealed whether the embryos had a normal number
of chromosomes, as chromosome abnormalities are one of
the main causes of miscarriage and failure of embryos
to form pregnancies during IVF treatments.
"This is the first time that embryonic DNA has been detected in the human blastocyst without the use of biopsy," explained lead researchers Dr. Simone Palini Ph.D., from the IVF Unit at Cervesi Hospital in Cattolica, Italy and Dr. Galluzzi from University of Urbino in Italy and Dr. Dagan Wells from University of Oxford, United Kingdom.
"This is a technique that most embryologists can easily master," Dr. Buletti who directs the IVF team at Cervesi Hospital Cattolica and Prof. Magnani, Chairman of the Department of Biomolecular Sciences of the University of Urbino, added. "More work needs to be done to confirm our results, but we hope that this approach will ultimately help infertile couples achieve their dream of having a family. It may also improve the options for families affected by severe inherited conditions, helping them to have healthy babies."
"Even though it is only a preliminary finding, this approach
may allow for genetic testing of the embryo without
the complexity of cell sampling."
Dr. Joe Leigh Simpson MD
Senior Vice President for Research Programs
March of Dimes Foundation
International Federation of Fertility Societies (IFFS)
(a pioneer in reproductive medicine and genetics)
This article is "Genomic DNA in human blastocoele fluid" by S. Palini, L. Galluzzi, S. De Stefani, M. Bianchi, D. Wells, M. Magnani, C. Bulletti (10.1016/j.rbmo.2013.02.012).The article is currently an Article in Press in Reproductive Biomedicine Online, (March, 2013), published by Elsevier.
About Reproductive Biomedicine Online
Reproductive Biomedicine Online (http://www.rbmojournal.com) covers the formation, growth and differentiation of the human embryo. It is intended to bring to public attention new research on biological and clinical research on human reproduction and the human embryo including relevant studies on animals. It is published by a group of scientists and clinicians working in these fields of study. Its audience comprises researchers, clinicians, practitioners, academics and patients.
Elsevier is a world-leading publisher of scientific, technical and medical information products and services. The company works in partnership with the global science and health communities to publish more than 2,000 journals, including The Lancet and Cell, and close to 20,000 book titles, including major reference works from Mosby and Saunders. Elsevier's online solutions include SciVerse ScienceDirect, SciVerse Scopus, Reaxys, MD Consult and Nursing Consult, which enhance the productivity of science and health professionals, and the SciVal suite and MEDai's Pinpoint Review, which help research and health care institutions deliver better outcomes more cost-effectively.
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Original article: http://www.eurekalert.org/pub_releases/2013-04/e-soe040213.php